Stdlib: vsprintf() and sscanf() — formatted I/O (ext/standard/sprintf.c parity)

[PurHur]

Category

stdlib

Problem

sprintf() exists, but vsprintf() (format + array of args) and sscanf() (parse string into variables) are missing. Zend stdlib and many PECL-style snippets depend on them; sscanf is the inverse of sprintf for simple parsers.

php-src reference

• php/php-src ext/standard/sprintf.c — php_vsprintf(), php_sprintf()
• php/php-src ext/standard/sscanf.c — php_sscanf(), php_sscanf_internal()
• php/php-src ext/standard/basic_functions.c — registrations

Repro (failure today)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r '"'"'echo vsprintf("%s-%d", ["a", 3]);'"'"''
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r '"'"'$n = 0; sscanf("42", "%d", $n); echo $n;'"'"''

Expected (Zend): a-3 and 42
Actual: undefined function for vsprintf / sscanf.

Scope (this repo)

• ext/standard/vsprintf.php, ext/standard/sscanf.php
• VM: host vsprintf / sscanf with reference-parameter lowering for $n out-args (see Language: Reference assignment and by-ref parameters #140 by-ref)
• ext/standard/Module.php
• JIT: reuse existing sprintf JIT helpers where possible, or VM-only v1
• test/compliance/cases/stdlib/vsprintf_basic.phpt, sscanf_int.phpt
• script/capability-matrix.php

Done when

• vsprintf('%s', ['ok']) === 'ok' on VM
• sscanf('10 20', '%d %d', $a, $b) assigns $a=10, $b=20 (VM reference args)
• Format/arg count mismatch warnings match Zend smoke tests
• Matrix documents VM/JIT/AOT columns

Labels

stdlib, phase-4:stdlib, area:vm, implementation-ready

Related

• sprintf() — existing lowering
• Language: Reference assignment and by-ref parameters #140 / Language: By-reference parameters JIT/AOT lowering (phase 2 post-#140) #3161 — by-reference parameters for sscanf out-args

[PurHur]

claim: PHP Compiler STD Lib — starting this run

[PurHur]

Merged via #3962

Verification (Docker):

• vendor/bin/phpunit --filter "vsprintf|sscanf" test/compliance/VMTest.php test/aot/AotTest.php — OK (VM + AOT PHPTs)
• php bin/vm.php -r 'echo vsprintf("%s-%d", ["a", 3]), "\n";' → a-3
• php bin/vm.php -r '$n=0; echo sscanf("42", "%d", $n), " ", $n, "\n";' → 1 42

JIT MCJIT execute still segfaults on hashtable argv packing (same as vfprintf); compliance JITTest skips these PHPTs; AOT + VM are green.