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std › process › argsAlloc

argsAlloc

Caller must call argsFree on result. On Windows, the result is encoded as WTF-8. On other platforms, the result is an opaque sequence of bytes with no particular encoding.

Function parameters

Parameters

#

Type definitions in this namespace

Types

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ArgIteratorWindows
Iterator that implements the Windows command-line parsing algorithm.
ArgIteratorGeneralOptions
Optional parameters for `ArgIteratorGeneral`
ArgIterator
Cross-platform command line argument iterator.

Functions in this namespace

Functions

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getCwd
The result is a slice of `out_buffer`, from index `0`.
getCwdAlloc
Caller must free the returned memory.
getEnvMap
Returns a snapshot of the environment variables of the current process.
getEnvVarOwned
Caller must free returned memory.
hasEnvVarConstant
On Windows, `key` must be valid WTF-8.
hasNonEmptyEnvVarConstant
On Windows, `key` must be valid WTF-8.
parseEnvVarInt
Parses an environment variable as an integer.
hasEnvVar
On Windows, if `key` is not valid [WTF-8](https://simonsapin.github.io/wtf-8/),
hasNonEmptyEnvVar
On Windows, if `key` is not valid [WTF-8](https://simonsapin.github.io/wtf-8/),
getenvW
Windows-only.
ArgIteratorGeneral
A general Iterator to parse a string into a set of arguments
args
Holds the command-line arguments, with the program name as the first entry.
argsWithAllocator
You must deinitialize iterator's internal buffers by calling `deinit` when done.
argsAlloc
Caller must call argsFree on result.
getUserInfo
POSIX function which gets a uid from username.
posixGetUserInfo
TODO this reads /etc/passwd.
execv
Replaces the current process image with the executed process.
execve
Replaces the current process image with the executed process.
totalSystemMemory
Returns the total system memory, in bytes as a u64.
cleanExit
Indicate that we are now terminating with a successful exit code.
raiseFileDescriptorLimit
Raise the open file descriptor limit.
createEnvironFromMap
Creates a null-delimited environment variable block in the format
createEnvironFromExisting
Creates a null-delimited environment variable block in the format
createWindowsEnvBlock
Caller must free result.
fatal
Logs an error and then terminates the process with exit code 1.

Error sets in this namespace

Error Sets

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Tells whether calling the `execv` or `execve` functions will be a compile error.

Values

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can_execv
Tells whether calling the `execv` or `execve` functions will be a compile error.
can_spawn
Tells whether spawning child processes is supported (e.g.

Source

Implementation

#
pub fn argsAlloc(allocator: Allocator) ![][:0]u8 {
    // TODO refactor to only make 1 allocation.
    var it = try argsWithAllocator(allocator);
    defer it.deinit();

    var contents = std.array_list.Managed(u8).init(allocator);
    defer contents.deinit();

    var slice_list = std.array_list.Managed(usize).init(allocator);
    defer slice_list.deinit();

    while (it.next()) |arg| {
        try contents.appendSlice(arg[0 .. arg.len + 1]);
        try slice_list.append(arg.len);
    }

    const contents_slice = contents.items;
    const slice_sizes = slice_list.items;
    const slice_list_bytes = try math.mul(usize, @sizeOf([]u8), slice_sizes.len);
    const total_bytes = try math.add(usize, slice_list_bytes, contents_slice.len);
    const buf = try allocator.alignedAlloc(u8, .of([]u8), total_bytes);
    errdefer allocator.free(buf);

    const result_slice_list = mem.bytesAsSlice([:0]u8, buf[0..slice_list_bytes]);
    const result_contents = buf[slice_list_bytes..];
    @memcpy(result_contents[0..contents_slice.len], contents_slice);

    var contents_index: usize = 0;
    for (slice_sizes, 0..) |len, i| {
        const new_index = contents_index + len;
        result_slice_list[i] = result_contents[contents_index..new_index :0];
        contents_index = new_index + 1;
    }

    return result_slice_list;
}