How can I read a environmental variable in Cocoa?

问题

How could I read an environmental variable that a user has set?

I'm new to desktop development on the Mac (cocoa), and I am building a little tool that I can use to access amazon's s3 service.

I set my environmental variables in my .bash_profile, but I want this to work regardless of where the user entered it (.bashrc, .bash_profile or .profile etc).

回答1:

Look at the environment method on a NSProcessInfo. It returns a NSDictionary of the environment so e.g. for PATH

NSString* path = [[[NSProcessInfo processInfo]environment]objectForKey:@"PATH"];

回答2:

You can use a C API from the GNU library http://www.gnu.org/software/libc/manual/html_node/Environment-Access.html#Environment-Access

converting to NSString: modern obj-c:

NSString *envVarString = @(getenv("__MY_ENV_NAME__"));

legacy obj-c:

NSString *envVarString = [NSString stringWithUTF8String: getenv("__MY_ENV_NAME__")];

来源：https://stackoverflow.com/questions/11550300/how-can-i-read-a-environmental-variable-in-cocoa