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.

# 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.

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.

tcc -isystem /opt/include source.c

-nostdinc · flag

Do not search the default system include paths. Only search include paths explicitly provided with -I.

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.

# 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.

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.

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.

# 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

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.

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.

// 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.

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.

tcc -ftest-coverage program.c -o program
./program
# Creates: program.tcov

Warning options

-w · flag

Disable all warnings.

tcc -w source.c

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.

# 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 *.

tcc -Wall -Wwrite-strings source.c

Linker options

Library paths

-Ldir · string

Add a directory to the library search path for the -l option.

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.

# 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.

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.

# 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.

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)

# 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.

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.

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.

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.

tcc -b program.c -o program
./program
# Runtime bounds checking active

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:

int tcc_backtrace(const char *fmt, ...);

Example:

# 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).

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)

tcc -xc header.h -xn source.c

-O[n] · flag

Define __OPTIMIZE__ macro for optimization level n. -O0 does not define the macro.

tcc -O2 source.c

TCC does minimal optimization. The -O flag mainly affects preprocessor macros for conditional compilation.

-pthread · flag

Preprocess with -D_REENTRANT and link with -lpthread.

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).

# 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).

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:

-arch -C --param -pedantic -pipe -s -traditional

Use -Wunsupported to get warnings about ignored GCC features and options.