std::perror(3)

💖 std::perror(3) 💖

okay bestie, you’re looking at std::perror(3) from the C++ Standard Libary, and we’re gonna get you fluent in it, no cap 🫶

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🌸 NAME 🌸

std::perror — std::perror (yes, that’s literally the NAME line, we’re keeping it exactly as the page says 💅)

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✨ Synopsis ✨

Defined in header <cstdio>:

void perror( const char *s );

okay so this 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).

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🦋 Parameters 🦋

• s — pointer to a null-terminated string with explanatory message

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💜 Return value 💜

(none)

literally nothing, bestie — (none) 🙈

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🌈 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

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🐚 See also 🐚

• errno — macro which expands to POSIX-compatible thread-local error number variable (macro variable)
• strerror — returns a text version of a given error code (function)
• C documentation for perror

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mwah 💋 source/version: http://cppreference.com, dated 2024.06.10 — byeee, go flex that error-message knowledge 🫶✨