diff options
Diffstat (limited to 'manuals/bc/E.1.md')
| -rw-r--r-- | manuals/bc/E.1.md | 52 |
1 files changed, 40 insertions, 12 deletions
diff --git a/manuals/bc/E.1.md b/manuals/bc/E.1.md index 85db83b1d2d8..cf52f5a2035e 100644 --- a/manuals/bc/E.1.md +++ b/manuals/bc/E.1.md @@ -504,40 +504,48 @@ The following are valid operands in bc(1): 7. **scale(E)**: The *scale* of **E**. 8. **abs(E)**: The absolute value of **E**. This is a **non-portable extension**. -9. **modexp(E, E, E)**: Modular exponentiation, where the first expression is +9. **is_number(E)**: **1** if the given argument is a number, **0** if it is a + string. This is a **non-portable extension**. +10. **is_string(E)**: **1** if the given argument is a string, **0** if it is a + number. This is a **non-portable extension**. +11. **modexp(E, E, E)**: Modular exponentiation, where the first expression is the base, the second is the exponent, and the third is the modulus. All three values must be integers. The second argument must be non-negative. The third argument must be non-zero. This is a **non-portable extension**. -10. **divmod(E, E, I[])**: Division and modulus in one operation. This is for +11. **divmod(E, E, I[])**: Division and modulus in one operation. This is for optimization. The first expression is the dividend, and the second is the divisor, which must be non-zero. The return value is the quotient, and the modulus is stored in index **0** of the provided array (the last argument). This is a **non-portable extension**. -11. **asciify(E)**: If **E** is a string, returns a string that is the first +12. **asciify(E)**: If **E** is a string, returns a string that is the first letter of its argument. If it is a number, calculates the number mod **256** and returns that number as a one-character string. This is a **non-portable extension**. -12. **I()**, **I(E)**, **I(E, E)**, and so on, where **I** is an identifier for +13. **asciify(I[])**: A string that is made up of the characters that would + result from running **asciify(E)** on each element of the array identified + by the argument. This allows creating multi-character strings and storing + them. This is a **non-portable extension**. +14. **I()**, **I(E)**, **I(E, E)**, and so on, where **I** is an identifier for a non-**void** function (see the *Void Functions* subsection of the **FUNCTIONS** section). The **E** argument(s) may also be arrays of the form **I[]**, which will automatically be turned into array references (see the *Array References* subsection of the **FUNCTIONS** section) if the corresponding parameter in the function definition is an array reference. -13. **read()**: Reads a line from **stdin** and uses that as an expression. The +15. **read()**: Reads a line from **stdin** and uses that as an expression. The result of that expression is the result of the **read()** operand. This is a **non-portable extension**. -14. **maxibase()**: The max allowable **ibase**. This is a **non-portable +16. **maxibase()**: The max allowable **ibase**. This is a **non-portable extension**. -15. **maxobase()**: The max allowable **obase**. This is a **non-portable +17. **maxobase()**: The max allowable **obase**. This is a **non-portable extension**. -16. **maxscale()**: The max allowable **scale**. This is a **non-portable +18. **maxscale()**: The max allowable **scale**. This is a **non-portable extension**. -17. **line_length()**: The line length set with **BC_LINE_LENGTH** (see the +19. **line_length()**: The line length set with **BC_LINE_LENGTH** (see the **ENVIRONMENT VARIABLES** section). This is a **non-portable extension**. -18. **global_stacks()**: **0** if global stacks are not enabled with the **-g** +20. **global_stacks()**: **0** if global stacks are not enabled with the **-g** or **-\-global-stacks** options, non-zero otherwise. See the **OPTIONS** section. This is a **non-portable extension**. -19. **leading_zero()**: **0** if leading zeroes are not enabled with the **-z** +21. **leading_zero()**: **0** if leading zeroes are not enabled with the **-z** or **--leading-zeroes** options, non-zero otherwise. See the **OPTIONS** section. This is a **non-portable extension**. @@ -811,6 +819,19 @@ The **if** **else** statement does the same thing as in C. The **quit** statement causes bc(1) to quit, even if it is on a branch that will not be executed (it is a compile-time command). +**Warning**: The behavior of this bc(1) on **quit** is slightly different from +other bc(1) implementations. Other bc(1) implementations will exit as soon as +they finish parsing the line that a **quit** command is on. This bc(1) will +execute any completed and executable statements that occur before the **quit** +statement before exiting. + +In other words, for the bc(1) code below: + + for (i = 0; i < 3; ++i) i; quit + +Other bc(1) implementations will print nothing, and this bc(1) will print **0**, +**1**, and **2** on successive lines before exiting. + The **halt** statement causes bc(1) to quit, if it is executed. (Unlike **quit** if it is on a branch of an **if** statement that is not executed, bc(1) does not quit.) @@ -1469,6 +1490,10 @@ at https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html . The flags **-efghiqsvVw**, all long options, and the extensions noted above are extensions to that specification. +In addition, the behavior of the **quit** implements an interpretation of that +specification that is different from all known implementations. For more +information see the **Statements** subsection of the **SYNTAX** section. + Note that the specification explicitly says that bc(1) only accepts numbers that use a period (**.**) as a radix point, regardless of the value of **LC_NUMERIC**. @@ -1478,7 +1503,10 @@ This bc(1) supports error messages for different locales, and thus, it supports # BUGS -None are known. Report bugs at https://git.yzena.com/gavin/bc. +Before version **6.1.0**, this bc(1) had incorrect behavior for the **quit** +statement. + +No other bugs are known. Report bugs at https://git.yzena.com/gavin/bc . # AUTHORS |