forums.ps2dev.org

[anmabagima]

Hi there,

I'm not sure whether this question was ever asked in this forum. However, I would like to understand why and when it is best suited to use either fopen or sceIoOpen to access files in read mode (and the corresponding functions to write etc...)

What is the difference between the functions - if there is one ?
I'm using manly the fopen/fread etc. function to access files in my homebrew - is there a knwon disadvantege in using them ?

Thanks in advance for any suggestions and advice.

[Davee]

fopen/fread/fwrite/fclose etc are the standard libc functions. They aren't "standard" in the PSP kernel so the sdk has wrappers for them which eventually translates them into sceIo* calls.

So the disadvantage is, is that it takes longer to use f* than it does sceIo*.

[victorprosa]

If you are able to do that, ALWAYS prefer Sce* functions, because it was designed especially for the PSP hardware, by guys that understand it better than us...
And, the standard libc functions are translated into Sce* functions, but usually you lost performance...

[anmabagima]

Hi there,

thanks for your replies. Just one thought: could I use sceIoOpen with PSPLINK in the same way I would use fopen ?
I just have seen that you need to pass a full qualified path to sceIoOpen in all the threads (starting whith device). I would assume that the device is different when using the homebrew with PSPLINK instead of from the memory stick. Am I right ?

Thanks for any hint.

[unsigned int]

You should be able to use the same file names for sceIoOpen and fopen. Looking at the source code for the PSPSDK libc the fopen function just passes the path through to sceIoOpen without altering it in any way.

[anmabagima]

Hi,

thanks for confirmation. I will give it a try :)

[anmabagima]

Hi,

I've tried sceIoOpen as I have used fopen. However, this results in error: 0x8002032c

fopen( params->fileName, "rb" ); works but sceIoOpen( params->fileName, PSP_O_RDONLY, 0777 ); does not. Any ideas ?

params->fileName = "testfile.txt"

Google returns "No Cwd ??" when searching for this error code...

Thanks for any hints...Am I assuming right I should pass "device:path/filename" to sceIoOpen ? If so, what is the path I need to put if I only know that the file is stored together with the Eboot on MS or together with the PRX on the harddisk using PSPLINK. In many threads I've seen MS0: as device for the memory stick, but shouldn't be host0: during PSPLINK ?

[Alberto]

[victorprosa]

I don't understand well what you are trying to do, but i may tell that:

Relative paths do work in SceIo, and all commands related to it, like "./" also does...
The initial path in SceIo is always the path of your homebrew, ie:

[anmabagima]

Hi victorprosa,

thanks for your reply. It is exactly what I've assumed and what I'm trying.

I'm calling sceIoOpen( "myFile.lol", PSP_O_RDONLY, 0777 ); which results in the error mentioned.
However, fopen("myFile.lol", "rb") does work.

In both cases it was tested using PSPLINK. In some circumstances I need to debug my code as it is evolving. I found PSPLINK very useful for this in the past. If this does not work with sceIoOpen than may be I need to choose the same approach and compile, pass to MS , execute and if it failes correct my code....

[Torch]

Seeing that NOTHING cross platform will ever compile for the PSP without extensive modification, it seems redundant to leave the fopen calls as such. You might as well convert everything to sce* while porting.

[hlide]

Always use sceIo* functions instead of f* functions. Why ? f* uses buffers. The issue is if you let PSP to go in standby whereas you have FILE* handles open, you'll get problem when you wake up your PSP.

[anmabagima]

Hi,

sorry for asking a stupid question, but what does this actually mean ?
Do I need to have a branch on each file activity statement which choses f* if compiling and running using PSPLINK and sceIo* when compiling finally fpr PSP memory stick ?

Thanks.

[unsigned int]

Just wanted to add that I stand corrected on my previous assumption that fopen() didn't change the path when calling sceIoOpen().

I found out that the PSPSDK libc implementation does this, but (unless otherwise specified in the Makefile) it is not used, but newlib is. And in there is in fact code to expand a relative path to a full path before calling sceIoOpen().

So it is probably the best to do what Alberto posted earlier, take the working directory from argv[0] and expand all filenames yourself.

[yokfran]

I think sceIo* is better.

If you use fopen, you have to manage these FILE* pointers yourself. And I think the SceUIDs that returns by all sce* functions, is managed by some sce* threads which are built inside the PSP system.
So you do less work than using fopen/f* etc.

If sceIoOpen returns error code, it's better to use abs-path.

Sample code.

int main(int args, char *argv[])
{
char bootpath[64], *ptr;//i think 64 is long enough
strcpy(bootpath, argv[0]);
ptr = strrchr(bootpath, '/');
*++ptr = 0;
//Boot directory is in bootpath now.
}

[anmabagima]

Hi,

thanks. will try this out.

Regards...

[jimparis]

sceIoOpen is buggy when it comes to relative paths. I don't recall the details, but the newlib wrappers just canonicalize everything before passing to sceIoOpen.

Unless you're really performance sensitive, you should use the newlib wrappers when available. They're easier to use (since they're well-documented everywhere) and we've already handled a whole mess of these sorts of bugs in the sce* interfaces.

[hlide]

[Alberto]

[jimparis]

[hlide]