i'm working in a sketch that loads data from a php page via loadstring().
but, if several users use my applet and execute the loadstring("http://somedomain.com/somefile.php") at the same time , what happens? will php execute them at the same time? one at a time?

lets think about a php script that reads and writes to a text file, lets say... it takes one second from start to finish the script, what happens? will a writing process start before the previous one finish?

i'm so sorry if this is not the right place to post about php, and... only about php, but i need it to  processing work i'm doing.

ok, ok... hum.... i understand what you mean... my fears can became true.
tell me what you think about this PhiLho,

lets pretend i have 100 users logged at all the time,

and i write something like this:

in the data base:

bool jobdonne; // value stored in MySQL to check if script is running.

Table taskqueue. // table where i store updates to the txt file.

then, in the script:

1* user sends data to web site.

2* data is stored in the taskqueue table database with some common script and keeps somekind of id of the record sent to the data base.

3* after data is stored in database checks jobdonne value.

if jobdonne is true, does nothing, it means updating script is running. job ends to that user.

but if jobdonne is false, and that means the updating script is not in use, them
changes jobdonne to true, to prevents other users from activating the updatefile script,
gets all the data with his inserted record and earlier records from
taskqueue table, update the txt file,
them changes jobdonne to false back again.

---- END ----


has we say in portugal, does this ideia have legs to walk?
to prevent failures when several users update the same text file?

the text file has a x number of lines tha is always the same, that doesn't change, only values in the lines.

i'll try to explain better....

i'll have, something what i can call "smal files", but i'll have lots of files.
those files will be geometry vertices processing will use.  each file will cover a section of the main geometry that users will work on.

like in a building site(main geometry), several workers(users) in a level(file), where each level is a file, and those workers will acess only that level(file), but with time, the building(main geometry) will grow up and that means more file, and i want every user when loading or saving his data, doesn't need do acess ALL the data in the database, but a small section of the main geometry stored in a small file.

a user will work in a file only to prevent the server to process everything all the time.

it's possible to have 2 users updating the same data at the same time, thats no problem, because i thought about that already, i just need to prevent the script updating each file not to corrupt the file, because that would be total FAIL, since is geometry data.

so, my ideia is to make a writing_file_script that will not  be executed
twice at the same time. THAT JUST CAN'T HAPPEN. and as you told me is is possible to happen, right?

if script is executed, it blocks it's self from execution and processes data from data_queue or something, after doing so, it unblocks it's self to be executed again. if script is blocked , data send by user goes to the data_queue only, if not blocked data goes to data queue the same way, but script is activated to process all data in data_queue.

i hoppe it works fine.....