> ## Documentation Index > Fetch the complete documentation index at: https://mintlify.com/TinyCC/tinycc/llms.txt > Use this file to discover all available pages before exploring further. # Command-line options > Complete reference for all TCC command-line options and flags ## Output options **-o outfile** `string` Specify the output filename for the object file, executable, or shared library. ```bash theme={null} # Generate executable tcc -o myprogram source.c # Generate object file tcc -c -o myobject.o source.c # Generate shared library tcc -shared -o libmylib.so mylib.c ``` **-c** `flag` Compile only - generate an object file without linking. **-run** `flag` Compile and run the program immediately with optional arguments. ## Preprocessor options ### Include paths **-Idir** `string` Add a directory to the include file search path. Include paths are searched in the order they are specified. System include paths are always searched after user-specified paths. ```bash theme={null} tcc -I/usr/local/mylib/include -I./include source.c ``` Default system include paths: * `/usr/local/include` * `/usr/include` * `PREFIX/lib/tcc/include` (usually `/usr/lib/tcc/include`) **-isystem dir** `string` Add a directory to the system include path. Files from system include paths are treated as system headers. ```bash theme={null} tcc -isystem /opt/include source.c ``` **-nostdinc** `flag` Do not search the default system include paths. Only search include paths explicitly provided with `-I`. ```bash theme={null} tcc -nostdinc -I./include source.c ``` ### Macro definitions **-Dsym\[=val]** `string` Define a preprocessor symbol. If `val` is not provided, the value is `1`. Function-like macros can also be defined. ```bash theme={null} # Define simple macro tcc -DDEBUG source.c # Define macro with value tcc -DVERSION=2 source.c # Define function-like macro tcc -D'MAX(a,b)=((a)>(b)?(a):(b))' source.c ``` **-Usym** `string` Undefine a preprocessor symbol. ```bash theme={null} tcc -U__STDC__ source.c ``` ### Include files **-include file** `string` Include the specified file before processing each input file, as if `#include "file"` appeared at the beginning. ```bash theme={null} tcc -include config.h source.c ``` ### Preprocessing output **-E** `flag` Preprocess only - output preprocessed source to stdout or file (with `-o`). **-P** `flag` With `-E`: do not output `#line` directives in preprocessed output. **-P1** `flag` With `-E`: output alternative `#line` directives. **-dD** `flag` With `-E`: output `#define` directives along with preprocessed code. **-dM** `flag` With `-E`: output only `#define` directives, no preprocessed code. ```bash theme={null} # Standard preprocessing tcc -E source.c # Preprocessing without line directives tcc -E -P source.c -o source.i # Show all macros tcc -E -dM - < /dev/null ``` **-Wp,-opt** `string` Pass option directly to preprocessor. Equivalent to using `-opt` directly. ## Compilation flags > [!NOTE] > > Most compilation flags support a negative form with the `-fno-` prefix to disable the feature. ### Character type **-funsigned-char** `flag` Make the `char` type unsigned by default. **-fsigned-char** `flag` Make the `char` type signed by default. ```bash theme={null} tcc -funsigned-char source.c ``` ### Symbol behavior **-fno-common** `flag` Do not generate common symbols for uninitialized global data. Place uninitialized globals in BSS instead. **-fleading-underscore** `flag` Add a leading underscore to the beginning of each C symbol (for compatibility with some platforms). ### Language extensions **-fms-extensions** `flag` Allow Microsoft C compiler extensions. Currently this enables anonymous struct/union declarations without an identifier to behave like unnamed members. ```c theme={null} // Enabled with -fms-extensions struct { int x; struct { int y; int z; }; // Anonymous struct - members accessible directly } data; // Access: data.y, data.z ``` **-fdollars-in-identifiers** `flag` Allow dollar signs (`$`) in C identifiers. ```c theme={null} int my$variable = 42; // Valid with -fdollars-in-identifiers ``` ### Function behavior **-freverse-funcargs** `flag` Evaluate function arguments from right to left instead of left to right. **-fgnu89-inline** `flag` Make `extern inline` behave like `static inline` (GNU89 semantics). ### Debug and analysis **-fasynchronous-unwind-tables** `flag` Generate exception handling frame section (`eh_frame`). This is enabled by default. **-ftest-coverage** `flag` Generate code coverage instrumentation. After running the program, a `.tcov` file is created with coverage data. ```bash theme={null} tcc -ftest-coverage program.c -o program ./program # Creates: program.tcov ``` ## Warning options **-w** `flag` Disable all warnings. ```bash theme={null} tcc -w source.c ``` > [!NOTE] > > Most warning options support a negative form with the `-Wno-` prefix. **-Wall** `flag` Enable commonly useful warnings. Includes: * `-Wimplicit-function-declaration` * `-Wdiscarded-qualifiers` **-Werror** `flag` Treat all warnings as errors. Can be given an option to enable a specific warning and treat it as an error. ```bash theme={null} # Treat all warnings as errors tcc -Werror source.c # Treat only unsupported warnings as errors tcc -Werror=unsupported source.c ``` ### Specific warnings **-Wimplicit-function-declaration** `flag` Warn when a function is called without a prior declaration or prototype. **-Wdiscarded-qualifiers** `flag` Warn when type qualifiers like `const` are dropped (e.g., assigning `const char *` to `char *`). **-Wunsupported** `flag` Warn about unsupported GCC features and options that are ignored by TCC. **-Wwrite-strings** `flag` Make string literals of type `const char *` instead of `char *`. ```bash theme={null} tcc -Wall -Wwrite-strings source.c ``` ## Linker options ### Library paths **-Ldir** `string` Add a directory to the library search path for the `-l` option. ```bash theme={null} tcc -L/usr/local/lib -L./lib source.c ``` Default library paths: * `/usr/local/lib` * `/usr/lib` * `/lib` ### Libraries **-lxxx** `string` Link with dynamic library `libxxx.so` or static library `libxxx.a`. Libraries are searched in paths specified by `-L` and the `LIBRARY_PATH` environment variable. ```bash theme={null} # Link with math library tcc source.c -lm # Link with multiple libraries tcc source.c -lpthread -lm -lrt ``` **-Bdir** `string` Set the path where TCC's internal libraries and include files are located. Default is `PREFIX/lib/tcc`. ### Library generation **-shared** `flag` Generate a shared library instead of an executable. **-soname name** `string` Set the shared object name (DT\_SONAME) to be used at runtime. **-static** `flag` Generate a statically linked executable. Links with static versions of libraries. This is not recommended as it may not work correctly with TCC. > [!WARNING] > > Static linking with `-static` is not fully supported and may not work correctly. TCC primarily targets dynamic linking. **-rdynamic** `flag` Export global symbols to the dynamic linker. Useful when a library opened with `dlopen()` needs to access symbols from the main executable. **-r** `flag` Generate a relocatable object file by combining all input files. ### Standard library options **-nostdlib** `flag` Do not implicitly link with the C standard library (`libc`), C runtime startup files, and `libtcc1`. **-Wl,-nostdlib** `flag` Do not search the default library paths. Only search paths specified with `-L` and the `LIBRARY_PATH` environment variable. ```bash theme={null} # Compile without standard library tcc -nostdlib -o program start.o program.c ``` ### Advanced linker options All options starting with `-Wl,` are passed to the linker: **-Wl,-rpath=path** `string` Set custom search path for dynamic libraries in the executable. ```bash theme={null} tcc -Wl,-rpath=/opt/lib source.c ``` **-Wl,--dynamic-linker=path** `string` Set the ELF interpreter (dynamic linker) path. **-Wl,-Ipath** `string` Alternative syntax for setting the dynamic linker path. **-Wl,--enable-new-dtags** `flag` Create the new ELF dynamic tag `DT_RUNPATH` instead of the legacy `DT_RPATH` when setting custom library search paths. **-Wl,--oformat=fmt** `string` Set the output format. Supported formats: * `elf32-i386` or `elf64-x86-64`: ELF format (default) * `binary`: Raw binary image (executables only) * `coff`: COFF format (TMS320C67xx target only) * `pe-i386` or `pe-x86-64`: PE format (Windows) ```bash theme={null} # Generate raw binary tcc -Wl,--oformat=binary bootloader.c -o boot.bin ``` **-Wl,--export-all-symbols** `flag` Same as `-rdynamic` - export all symbols to dynamic linker. **-Wl,--export-dynamic** `flag` Same as `-rdynamic` - export all symbols to dynamic linker. **-Wl,-Bsymbolic** `flag` Set the `DT_SYMBOLIC` ELF tag, which makes symbol resolution within the library prefer local definitions. **-Wl,--whole-archive** `flag` Include all object files from subsequent static libraries, not just those needed to resolve undefined symbols. **-Wl,--no-whole-archive** `flag` Return to normal behavior - only load objects as needed from static libraries. ```bash theme={null} tcc -Wl,--whole-archive -lmylib -Wl,--no-whole-archive source.c ``` ### Executable layout (Advanced) **-Wl,-Ttext=address** `string` Set the base address of the code section. **-Wl,--image-base=address** `string` Set the base address of the executable. **-Wl,--section-alignment=size** `string` Set section alignment in the executable. **-Wl,--file-alignment=size** `string` Set file alignment (PE format only). **-Wl,--stack=size** `string` Set stack reserve size (PE format only). ### Windows-specific options **-Wl,--subsystem=type** `string` Set PE (Windows) executable subsystem type: `console`, `gui`, `wince`, etc. ```bash theme={null} tcc -Wl,--subsystem=console program.c -o program.exe ``` ## Debugger options **-g** `flag` Generate runtime debug information in STAB format. Provides clear error messages like `test.c:68: in function 'test5()': dereferencing invalid pointer` instead of just `Segmentation fault`. ```bash theme={null} tcc -g program.c -o program ``` **-gdwarf** `flag` Generate runtime debug information in DWARF format instead of STAB. **-gdwarf-x** `flag` Generate extended DWARF debug information. **-g.pdb** `flag` Create a `.pdb` debug database file (Windows PE targets only). **-b** `flag` Compile with built-in memory and bounds checker. Detects memory allocation errors and array/pointer bounds violations at runtime. Implies `-g`. ```bash theme={null} tcc -b program.c -o program ./program # Runtime bounds checking active ``` > [!WARNING] > > The bounds checker (`-b`) adds significant runtime overhead. Only use during development and testing. **-bt\[N]** `flag` Link with backtrace support and display up to N callers in stack traces. Useful with `-g` or `-b`. Defines the `__TCC_BACKTRACE__` macro. Provides access to: ```c theme={null} int tcc_backtrace(const char *fmt, ...); ``` Example: ```bash theme={null} # Show up to 10 callers in stack traces tcc -bt10 -g program.c -o program ``` ## Miscellaneous options **-std=version** `string` Define the `__STDC_VERSION__` macro. Use `c11` or `gnu11` for C11 standard (sets to `201112`), otherwise sets to `199901` (C99). ```bash theme={null} tcc -std=c11 source.c ``` **-x type** `string` Specify the type of the next input file: * `c`: C source file * `a`: Assembly file * `b`: Binary file * `n`: None (reset to auto-detection) ```bash theme={null} tcc -xc header.h -xn source.c ``` **-O\[n]** `flag` Define `__OPTIMIZE__` macro for optimization level `n`. `-O0` does not define the macro. ```bash theme={null} tcc -O2 source.c ``` > [!NOTE] > > TCC does minimal optimization. The `-O` flag mainly affects preprocessor macros for conditional compilation. **-pthread** `flag` Preprocess with `-D_REENTRANT` and link with `-lpthread`. ```bash theme={null} tcc -pthread threaded_program.c ``` ### Dependency generation **-M** `flag` Output Makefile dependency rules instead of compiling. Includes system headers. **-MM** `flag` Like `-M` but only mention user header files, not system headers. **-MD** `flag` Generate Makefile dependency file while also compiling. **-MMD** `flag` Like `-MD` but only mention user header files. **-MF depfile** `string` Specify the output filename for dependency information (use with `-MD` or `-MMD`). **-MP** `flag` Add phony targets for each dependency (prevents make errors if headers are removed). ```bash theme={null} # Generate dependencies while compiling tcc -MMD -MF source.d -c source.c # Generate only dependencies tcc -MM source.c > source.d ``` **-dt** `flag` With `-run` or `-E`: automatically define `test_...` macros for testing purposes. ## Target-specific options **-m32** `flag` Generate 32-bit code (defer to i386 cross compiler if needed). **-m64** `flag` Generate 64-bit code (defer to x86\_64 cross compiler if needed). ```bash theme={null} tcc -m32 source.c -o program32 ``` **-mms-bitfields** `flag` Use Microsoft Visual C++ algorithm for bitfield layout instead of GCC's algorithm. **-mfloat-abi** `string` Select floating-point ABI on ARM. Values: `softfp` or `hard`. **-mno-sse** `flag` Do not use SSE registers for floating-point operations on x86\_64. ## Ignored options The following GCC options are recognized but ignored for compatibility: ```bash theme={null} -arch -C --param -pedantic -pipe -s -traditional ``` > [!TIP] > > Use `-Wunsupported` to get warnings about ignored GCC features and options. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.