[petsc-dev] [petsc-users] PetscPrintf

[Jed Brown]

"Smith, Barry F." <bsmith at mcs.anl.gov> writes:

>> On Apr 12, 2018, at 3:59 AM, Patrick Sanan <patrick.sanan at gmail.com> wrote:
>> 
>> I also happened to stumble across this yesterday. Is the length restriction for the default printer (l assume from the array of 8*1024 chars in PetscVFPrintfDefault() ) intended behavior to be documented, or a bug to be fixed?
>
>      You could call it either. My problems are 
>
> 1) that given a format string I don't know in advance how much work space is needed so cannot accurately malloc, for sure, enough space
>
> 2) since this can be called in an error handler I really don't want it calling malloc().
>
>    Hence it lives in this limbo. I don't even know a way to add a good error checking that detects if the buffer is long enough. All in all it is bad ugly code, any suggestions on improvements would be appreciated.

Is the postprocessing of output in PetscVSNPrintf really necessary?
Without it, you would call vfprintf instead of vsnprintf followed by
fprintf("%s", string) [1].


[1] fputs would be preferable.

>
>    Barry
>
>> 
>> 2018-04-12 2:16 GMT+02:00 Rongliang Chen <rongliang.chan at gmail.com>:
>> Thanks Barry. I found petsc-3.6 and older versions did not have this restriction.
>> 
>> Best,
>> Rongliang
>> 
>> 
>> On 04/12/2018 07:22 AM, Smith, Barry F. wrote:
>>    Yes, PetscPrintf() and related functions have a maximum string length of about 8000 characters.
>> 
>>     Barry
>> 
>> 
>> On Apr 11, 2018, at 6:17 PM, Rongliang Chen <rongliang.chan at gmail.com> wrote:
>> 
>> Dear All,
>> 
>> 
>> When I tried to print a long string using PetscPrintf() I found that it truncated the string. Attached is a simple example for this (run with single processor). I used PetscPrintf() and printf() to print the same string and the printf() seems OK. I am using petsc-3.8.4.
>> 
>> 
>> Best,
>> 
>> Rongliang
>> 
>> <ex111.c>
>> 
>> 
>>