VxWorks是否支持strptime()函数？需自行实现该功能吗？

Hey there! Let's clear this up right away: VxWorks does not include the POSIX-standard strptime() function by default. This function, which is super handy for parsing string representations of time into a struct tm structure, isn't part of VxWorks' standard C library subset.

So yes—if you need this functionality, you'll have to either implement it yourself or use alternative approaches that work within VxWorks' ecosystem. Here are a few practical options:

Option 1: Manual parsing with sscanf() #

If your time string follows a fixed, predictable format (like YYYY-MM-DD HH:MM:SS), sscanf() can get the job done easily. You just extract each time component and map it to the correct fields in struct tm:

#include <time.h>
#include <stdio.h>

int str_to_tm(const char* time_str, struct tm* tm_out) {
    // Adjust the format string to match your input's structure
    int year, month, day, hour, min, sec;
    if (sscanf(time_str, "%d-%d-%d %d:%d:%d", &year, &month, &day, &hour, &min, &sec) != 6) {
        return -1; // Parsing failed
    }
    
    // Remember: struct tm uses 0-based months and year offset from 1900
    tm_out->tm_year = year - 1900;
    tm_out->tm_mon = month - 1;
    tm_out->tm_mday = day;
    tm_out->tm_hour = hour;
    tm_out->tm_min = min;
    tm_out->tm_sec = sec;
    tm_out->tm_isdst = -1; // Let the system determine daylight saving time
    
    return 0;
}

This is a lightweight, no-fuss solution for fixed-format use cases. Just make sure to add validation for edge cases (like invalid month/day values) if needed.

Option 2: Port an open-source strptime implementation #

If you need the flexibility of supporting multiple format strings (just like the standard strptime()), you can find a lightweight, dependency-free open-source implementation of strptime and adapt it to VxWorks. Many embedded-focused projects have these available—just drop the relevant source files into your VxWorks project and adjust any compiler flags or platform-specific code as needed.

Option 3: Check for VxWorks-specific alternatives #

Some versions of VxWorks include a function called timeStringToTm() which serves a similar purpose (parsing time strings into struct tm). It's worth checking your VxWorks version's official API documentation to see if this or any other platform-specific time-parsing functions are available to you.

Just a quick note: If you go the custom implementation route, don't forget to handle edge cases like invalid dates, timezone considerations, and daylight saving time to ensure your time structures are accurate.

内容的提问来源于stack exchange，提问作者Chris