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std::perror(3)		       C++ Standard Libary		  std::perror(3)

NAME
     std::perror - std::perror

Synopsis
	Defined in header <cstdio>
	void perror( const char *s );

	Prints	a  textual description of the error code currently stored in the
     system
	variable errno to stderr.

	The description is formed by concatenating the following components:

	  * the contents of the null-terminated byte string  pointed  to  by  s,
     followed by ":
	    "  (unless	s  is a null pointer or the character pointed to by s is
     the null
	    character).
	  * implementation-defined error message  string  describing  the  error
     code stored in
	    errno,  followed  by  '\n'. The error message string is identical to
     the result of
	    std::strerror(errno).

Parameters
	s - pointer to a null-terminated string with explanatory message

Return value
	(none)

Example
     // Run this code

      #include <cerrno>
      #include <cmath>
      #include <cstdio>

      int main()
      {
	  double not_a_number = std::log(-1.0);
	  if (errno == EDOM)
	      std::perror("log(-1) failed");
	  std::printf("%f\n", not_a_number);
      }

Possible output:
      log(-1) failed: Numerical argument out of domain
      nan

See also
	errno	 macro which expands to POSIX-compatible thread-local error num-
     ber variable
		 (macro variable)
	strerror returns a text version of a given error code
		 (function)
	C documentation for
	perror

http://cppreference.com 	   2024.06.10			  std::perror(3)
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