---
name: "mkc_check_decl"
section: "1"
platform: "linux"
package: "mk-configure"
version: "0.40.3-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/mkc_check_decl"
---

# mkc\_check\_decl(1)

checks for define, variable, function, type, member or function prototype.

## NAME

mkc\_check\_decl - checks for define, variable, function, type, member or function prototype.

## SYNOPSIS

**mkc\_check\_decl** *\[OPTIONS\] \<check\_type\> \<what\> \[headers...\]*

## DESCRIPTION

*check\_type* is either  *define*, *variable*, *func\[0-9\]*, *funcordefine\[0-9\]*, *type*, *member* or  *prototype*. Depending on its value **mkc\_check\_decl** checks respectively for define, variable, function with the specified number of arguments (or equivalent define in case of funcordefine\[0-9\]), data type, member of structure or a function prototype in the specified *headers* by compiling a test program. *headers* is either a single header file or a list of headers, separated by comma. As a result **mkc\_check\_decl** prints either 1 (success) or 0 (failure) to stdout. By default, temporary and cache files \_mkc\_*\<check\_type\>*\_*\<what\>*\_*\<lheader\_h\>*.{c,err,res} are created under **MKC\_CACHEDIR** directory. Here, *lheader\_h* is the last header from comma-separated list *headers*.

## OPTIONS

- **-h**

  Display help message.

- **-d**

  Delete cache and temporary files.

- **-D**

  Delete cache files.

## ENVIRONMENT

- **CC**

  Compiler. By default *cc* is used.

- **CPPFLAGS, CFLAGS**

  Options passed to the compiler, for example -I for additional directories that contain header files.

- **MKC\_VERBOSE**

  If set to 1, verbose messages are output to stderr.

- **MKC\_SHOW\_CACHED**

  If set to 1 and MKC\_VERBOSE is set to 1, cached results are output to stderr.

- **MKC\_COMMON\_HEADERS**

  List of header files to add to .c test program.

- **MKC\_CACHEDIR**

  Directory where temporary and cache files are created. If unset they are created in a current directory.

- **MKC\_NOCACHE**

  All results are cached unless MKC\_NOCACHE variable is set to 1.

- **MKC\_DELETE\_TMPFILES**

  If set to 1, temporary files are removed.

## EXAMPLES

```
   mkc_check_decl define __GNUC__
   mkc_check_decl define RTLD_LAZY dlfcn.h
   mkc_check_decl define FTS_W sys/types.h,sys/stat.h,fts.h
   mkc_check_decl variable sys_errlist errno.h
   mkc_check_decl variable __malloc_hook malloc.h
   mkc_check_decl func3 poll poll.h
   mkc_check_decl func2 fgetln stdio.h
   mkc_check_decl type mbstate_t wchar.h
   mkc_check_decl type long-long
   mkc_check_decl member tm.tm_isdst time.h
   mkc_check_decl member ifreq.ifr_addr.sa_len net/if.h
   mkc_check_decl member struct-stat.st_mtimespec sys/stat.h
   mkc_check_decl prototype 'int connect(int,const struct sockaddr*,socklen_t)' sys/socket.h
   mkc_check_decl prototype 'int connect(int,struct sockaddr*,socklen_t)' sys/socket.h
```

## C FILE CONTENT

- **define**

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  #if defined(WHAT)
  int func(void)
  {
     return 0;
  }
  #else
  #error "WHAT is not a define"
  #endif
  ```

- **variable**

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  int func(void)
  {
     return sizeof ((WHAT)) && (&WHAT != 0);
  }
  ```

- **func3** (example for function with 3 arguments)

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  void func (void)
  {
     if (WHAT) return;
     WHAT(0,0,0);
  }
  ```

- **funcordefine3** (example for function/define with 3 arguments)

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  void func (void)
  {
     WHAT(0,0,0);
  }
  ```

- **type**

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  int func(void)
  {
     return sizeof (WHAT);
  }
  ```

- **member (example for struct stat.st\_mtimespec)**

  ```
  #include <sys/stat.h>
  int func(void)
  {
     struct_stat var;
     return sizeof (var.st_mtimespec);
  }
  ```

- **prototype** (example for void ttt(int,char\*\*) function)

  ```
  #include <header1.h>
   ...
  #include <headerN.h>
  void func (void);
  void func2 (void);
  void func (void)
  {
     if (ttt) return;
  }
  void ttt(int, char**);
  void func2 (void)
  {
     if (ttt) return;
  }
  ```

## AUTHOR

Aleksey Cheusov \<vle@gmx.net\>