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IntTryFromStr

IntTryFromStr

Description

Parse a decimal string into an integer. An optional leading + is accepted; underscore separators between digits are silently skipped.

Parameters

Name Direction Description
out in,out Int to overwrite with the parsed value. Must already be a valid initialised Int; its allocator is reused for the parsed result.
decimal in Null-terminated decimal string, optionally prefixed with +.

Success

Returns true. *out is deinitialised and replaced with the normalised parsed value.

Failure

Returns false on a non-decimal character, an empty digit run, or an allocation failure during accumulation. *out retains its pre-call value.

Usage example (Cross-references)

Usage examples (Cross-references) 
        }
    
        if (!IntTryFromStr(&result.significand, &digits)) {
            goto fail;
        }
        Int  parsed = IntFromStr("12x3", ALLOCATOR_OF(&alloc));
        Int  value  = IntInit(ALLOCATOR_OF(&alloc));
        bool result = !IntTryFromStr(&value, "12x3");
    
        result = result && IntIsZero(&parsed);
    
    bool test_int_try_from_decimal_null(void) {
        WriteFmt("Testing IntTryFromStr NULL handling\n");
    
        DefaultAllocator alloc = DefaultAllocatorInit();
    
        Int value = IntInit(ALLOCATOR_OF(&alloc));
        IntTryFromStr(&value, (Zstr)NULL);
        IntDeinit(&value);
        DefaultAllocatorDeinit(&alloc);
        Str  text   = StrInitFromZstr("123", &alloc);
        Int  out    = IntInit(&alloc.base);
        bool parsed = IntTryFromStr(&out, &text);
    
        bool result = parsed && (IntToU64(&out) == 123);
        Str  text   = StrInitFromZstr("+5", &alloc);
        Int  out    = IntInit(&alloc.base);
        bool parsed = IntTryFromStr(&out, &text);
    
        bool result = parsed && (IntToU64(&out) == 5);
        const char *text = "+5";
    
        bool ok     = IntTryFromStr(&out, text);
        bool result = ok;
        result      = result && (IntToU64(&out) == 5u);
        const char *text = "42";
    
        bool ok     = IntTryFromStr(&out, text);
        bool result = ok;
        result      = result && (IntToU64(&out) == 42u);
        Int out = IntFrom(987654321u, a); // pre-populated: holds a live buffer
    
        bool ok = IntTryFromStr(&out, "123456789");
        ok      = ok && IntToU64(&out) == 123456789u;
Last updated on
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