Tiny C Compiler Reference Documentation

Introduction

TCC compiles so fast that even for big projects Makefiles may not be necessary.

TCC can also be used to make C scripts, i.e. pieces of C source that you run as a Perl or Python script. Compilation is so fast that your script will be as fast as if it was an executable.

Exact differences with ANSI C

• The preprocessor tokens are the same as C. It means that in some rare cases, preprocessed numbers are not handled exactly as in ANSI C. This approach has the advantage of being simpler and FAST!
• Floating point numbers are not fully supported yet (some implicit casts are missing).
• Some typing errors are not signaled.

ISOC99 extensions

• 'inline' keyword is ignored.
• 'restrict' keyword is ignored.
• '__func__' is a string variable containing the current function name.
• Variadic macros: __VA_ARGS__ can be used for function-like macros:

      #define dprintf(level, __VA_ARGS__) printf(__VA_ARGS__)
  

  dprintf can then be used with a variable number of parameters.
• Declarations can appear anywhere in a block as in C++.
• Array and struct/union elements can be initialized in any order by using designators:

      struct { int x, y; } st[10] = { [0].x = 1, [0].y = 2 };
  
      int tab[10] = { 1, 2, [5] = 5, [9] = 9};
  

• Compound initializers are supported:

      int *p = (int []){ 1, 2, 3 };
  

  to initialize a pointer pointing to an initialized array. The same works for structures and strings.
• The boolean type '_Bool' is supported.
• 'long long' types not supported yet, except in type definition or 'sizeof'.
• Hexadecimal floating point constants are supported:

            double d = 0x1234p10;
  

  is the same as writing

            double d = 4771840.0;
  

GNU C extensions

• array designators can be used without '=':

      int a[10] = { [0] 1, [5] 2, 3, 4 };
  

• Structure field designators can be a label:

      struct { int x, y; } st = { x: 1, y: 1};
  

  instead of

      struct { int x, y; } st = { .x = 1, .y = 1};
  

• '\e' is ASCII character 27.

TinyCC extensions

• __TINYC__ is a predefined macro to '1' to indicate that you use TCC.
• '#!' at the start of a line is ignored to allow scripting.
• Binary digits can be entered ('0b101' instead of '5').

Command line invokation

usage: tcc [-Idir] [-Dsym] [-llib] [-i infile] infile [infile_args...]