Function getenv [src]

Get an environment variable. See also getenvZ.
Prototype

pub fn getenv(key: []const u8) ?[:0]const u8
Parameters

key: []const u8
Source

  pub fn getenv(key: []const u8) ?[:0]const u8 {
    if (native_os == .windows) {
        @compileError("std.posix.getenv is unavailable for Windows because environment strings are in WTF-16 format. See std.process.getEnvVarOwned for a cross-platform API or std.process.getenvW for a Windows-specific API.");
    }
    if (mem.indexOfScalar(u8, key, '=') != null) {
        return null;
    }
    if (builtin.link_libc) {
        var ptr = std.c.environ;
        while (ptr[0]) |line| : (ptr += 1) {
            var line_i: usize = 0;
            while (line[line_i] != 0) : (line_i += 1) {
                if (line_i == key.len) break;
                if (line[line_i] != key[line_i]) break;
            }
            if ((line_i != key.len) or (line[line_i] != '=')) continue;

            return mem.sliceTo(line + line_i + 1, 0);
        }
        return null;
    }
    if (native_os == .wasi) {
        @compileError("std.posix.getenv is unavailable for WASI. See std.process.getEnvMap or std.process.getEnvVarOwned for a cross-platform API.");
    }
    // The simplified start logic doesn't populate environ.
    if (std.start.simplified_logic) return null;
    // TODO see https://github.com/ziglang/zig/issues/4524
    for (std.os.environ) |ptr| {
        var line_i: usize = 0;
        while (ptr[line_i] != 0) : (line_i += 1) {
            if (line_i == key.len) break;
            if (ptr[line_i] != key[line_i]) break;
        }
        if ((line_i != key.len) or (ptr[line_i] != '=')) continue;

        return mem.sliceTo(ptr + line_i + 1, 0);
    }
    return null;
}  