diff options
Diffstat (limited to 'Documentation/printk-formats.txt')
| -rw-r--r-- | Documentation/printk-formats.txt | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt index 5a615c14f75d..cb6a596072bb 100644 --- a/Documentation/printk-formats.txt +++ b/Documentation/printk-formats.txt @@ -8,6 +8,21 @@ If variable is of Type, use printk format specifier: unsigned long long %llu or %llx size_t %zu or %zx ssize_t %zd or %zx + s32 %d or %x + u32 %u or %x + s64 %lld or %llx + u64 %llu or %llx + +If <type> is dependent on a config option for its size (e.g., sector_t, +blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a +format specifier of its largest possible type and explicitly cast to it. +Example: + + printk("test: sector number/total blocks: %llu/%llu\n", + (unsigned long long)sector, (unsigned long long)blockcount); + +Reminder: sizeof() result is of type size_t. + Raw pointer value SHOULD be printed with %p. The kernel supports the following extended format specifiers for pointer types: @@ -54,6 +69,7 @@ Struct Resources: For printing struct resources. The 'R' and 'r' specifiers result in a printed resource with ('R') or without ('r') a decoded flags member. + Passed by reference. Physical addresses types phys_addr_t: @@ -132,6 +148,8 @@ MAC/FDDI addresses: specifier to use reversed byte order suitable for visual interpretation of Bluetooth addresses which are in the little endian order. + Passed by reference. + IPv4 addresses: %pI4 1.2.3.4 @@ -146,6 +164,8 @@ IPv4 addresses: host, network, big or little endian order addresses respectively. Where no specifier is provided the default network/big endian order is used. + Passed by reference. + IPv6 addresses: %pI6 0001:0002:0003:0004:0005:0006:0007:0008 @@ -160,6 +180,8 @@ IPv6 addresses: print a compressed IPv6 address as described by http://tools.ietf.org/html/rfc5952 + Passed by reference. + IPv4/IPv6 addresses (generic, with port, flowinfo, scope): %pIS 1.2.3.4 or 0001:0002:0003:0004:0005:0006:0007:0008 @@ -186,6 +208,8 @@ IPv4/IPv6 addresses (generic, with port, flowinfo, scope): specifiers can be used as well and are ignored in case of an IPv6 address. + Passed by reference. + Further examples: %pISfc 1.2.3.4 or [1:2:3:4:5:6:7:8]/123456789 @@ -207,6 +231,8 @@ UUID/GUID addresses: Where no additional specifiers are used the default little endian order with lower case hex characters will be printed. + Passed by reference. + dentry names: %pd{,2,3,4} %pD{,2,3,4} @@ -216,6 +242,8 @@ dentry names: equivalent of %s dentry->d_name.name we used to use, %pd<n> prints n last components. %pD does the same thing for struct file. + Passed by reference. + struct va_format: %pV @@ -231,23 +259,20 @@ struct va_format: Do not use this feature without some mechanism to verify the correctness of the format string and va_list arguments. -u64 SHOULD be printed with %llu/%llx: - - printk("%llu", u64_var); + Passed by reference. -s64 SHOULD be printed with %lld/%llx: +struct clk: - printk("%lld", s64_var); + %pC pll1 + %pCn pll1 + %pCr 1560000000 -If <type> is dependent on a config option for its size (e.g., sector_t, -blkcnt_t) or is architecture-dependent for its size (e.g., tcflag_t), use a -format specifier of its largest possible type and explicitly cast to it. -Example: + For printing struct clk structures. '%pC' and '%pCn' print the name + (Common Clock Framework) or address (legacy clock framework) of the + structure; '%pCr' prints the current clock rate. - printk("test: sector number/total blocks: %llu/%llu\n", - (unsigned long long)sector, (unsigned long long)blockcount); + Passed by reference. -Reminder: sizeof() result is of type size_t. Thank you for your cooperation and attention. |