RFR: 8303942: os::write should write completely [v4]

[Afshin Zafari]

On Mon, 8 May 2023 01:41:27 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Afshin Zafari has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8303942: os::write should write completely
>
> src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp line 378:
> 
>> 376:       assert(size > 0, "invariant");
>> 377:       unsigned int bytes_read = 0;
>> 378:       unsigned int bytes_written = 0;
> 
> Why have you changed this to a 32-bit type?

Changed back to `int64_t`.

> src/hotspot/share/runtime/os.hpp line 232:
> 
>> 230:   static void  get_summary_cpu_info(char* buf, size_t buflen);
>> 231:   static void  get_summary_os_info(char* buf, size_t buflen);
>> 232:   static ssize_t pd_write(int fd, const void *buf, size_t nBytes);
> 
> What is the required meaning of the return value here? I'm assuming < 0 -> error; while >= 0 -> bytes written?

Comment added.

> src/hotspot/share/runtime/os.hpp line 649:
> 
>> 647:   static ssize_t read_at(int fd, void *buf, unsigned int nBytes, jlong offset);
>> 648:   // Writes the bytes completely. Returns 0 on success, -1 otherwise.
>> 649:   static ssize_t write(int fd, const void *buf, size_t nBytes);
> 
> We don't need a ssize_t return type if we only return -1 or 0. Also this should be specified to return OS_ERR on error and OS_OK on success. The callers should also check for OS_ERR and OS_OK rather than -1, < 0, > 0 etc.
> 
> Or we could simply make this a boolean function.

Return value changed to `bool`. All calls changed accordingly.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13750#discussion_r1187366331
PR Review Comment: https://git.openjdk.org/jdk/pull/13750#discussion_r1187367072
PR Review Comment: https://git.openjdk.org/jdk/pull/13750#discussion_r1187367995