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How do I get the list of all environment variables in C and/or C++?
I know that getenv can be used to read an environment variable, but how do I list them all?
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Using the printenv Command Or, if we run the command without arguments, it will display all environment variables of the current shell.
To list all the environment variables, use the command " env " (or " printenv "). You could also use " set " to list all the variables, including all local variables.
Select Start > All Programs > Accessories > Command Prompt. In the command window that opens, enter set. A list of all the environment variables that are set is displayed in the command window.
To export a environment variable you run the export command while setting the variable. We can view a complete list of exported environment variables by running the export command without any arguments. To view all exported variables in the current shell you use the -p flag with export.
The environment variables are made available to main() as the envp argument - a null terminated array of strings:
int main(int argc, char **argv, char **envp) { for (char **env = envp; *env != 0; env++) { char *thisEnv = *env; printf("%s\n", thisEnv); } return 0; } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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