std::getenv

Header: <cstdlib>

Searches the environment list provided by the host environment (the OS), for a string that matches the C string pointed to by env_var and returns a pointer to the C string that is associated with the matched environment list member.

# Declarations

char* getenv( const char* env_var );

# Parameters

• env_var: null-terminated character string identifying the name of the environmental variable to look for

# Return value

Character string identifying the value of the environmental variable or null pointer if such variable is not found.

# Notes

On POSIX systems, the environment variables are also accessible through the global variable environ, declared as extern char** environ; in <unistd.h>, and through the optional third argument, envp, of the main function.

# Example

#include <cstdlib>
#include <iostream>
 
int main()
{
    if (const char* env_p = std::getenv("PATH"))
        std::cout << "Your PATH is: " << env_p << '\n';
}

# See also

• C documentation