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2.2 ctype.h

2.1 assert.h

The assert header is used for debugging purposes.

Macros:

assert();
External References:
NDEBUG

2.1.1 assert

Declaration:

void assert(int expression);
The assert macro allows diagnostic information to be written to the standard error file.

If expression evaluates to 0 (false), then the expression, sourcecode filename, and line number are sent to the standard error, and then calls the abort function. If the identifier NDEBUG ("no debug") is defined with #define NDEBUG then the macro assert does nothing.

Common error outputting is in the form:

Assertion failed: expression, file filename, line line-number
Example: 
#include<assert.h>

void open_record(char *record_name)
{
  assert(record_name!=NULL);
  /* Rest of code */
}

int main(void)
{
  open_record(NULL);
}
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2.2 ctype.h